1. Field of the Invention
The present invention relates to a gas turbine engine combustor having at least one trapped vortex cavity and, more particularly, to a fuel injector bar used for injecting fuel into such cavity and flow passages of a dome inlet module providing high inlet air flows to the combustion chamber.
2. Description of Related Art
Advanced aircraft gas turbine engine technology requirements are driving the combustors therein to be shorter in length, have higher performance levels over wider operating ranges, and produce lower exhaust pollutant emission levels. One example of a combustor designed to achieve these objectives is disclosed in U.S. Pat. No. 5,619,855 to Burrus. As seen therein, the Burrus combustor is able to operate efficiently at inlet air flows having a high subsonic Mach Number. This stems in part from a dome inlet module which allows air to flow freely from an upstream compressor to the combustion chamber, with fuel being injected into the flow passage. The combustor also has inner and outer liners attached to the dome inlet module which include upstream cavity portions for creating a trapped vortex of fuel and air therein, as well as downstream portions extending to the turbine nozzle.
It will be noted in the aforementioned Burrus combustor that the fuel is injected into the trapped vortex cavities through a portion of the liner forming an aft wall of such cavity. Fuel is also injected into the flow passages of the dome inlet module via atomizers located along hollow vanes of the dome inlet module, the vanes being in flow communication with a fuel manifold. While functional for its intended purpose, it has been found that the fuel injection approach taken in the '855 patent lacks simplicity. In particular, it will be understood that this design requires the occupation of significant space within the combustor housing cavity, as separate systems are utilized for injecting the fuel into the cavities and the dome inlet module. This not only represents a large cost from a manufacturing standpoint, but extraction of fuel injectors from the engine for repair or replacement requires a major tear down of the engine to expose the combustor cavity section.
Accordingly, it would be desirable for a fuel injection system to be developed in which the cavity sections of a combustion chamber and the flow passages providing air flow thereto can be provided fuel in a simpler design requiring less space. Further, it would be desirable if such fuel injection system would be constructed so as to interface with the dome inlet module in a manner which enables easy access to the fuel injectors for repair and replacement.